摘要:
A multi-antenna channel estimation method based on polyphase decomposition includes: receiving frequency domain received signals transformed using discrete fourier transformation (DFT) in pilot symbols; performing phase correction on the frequency domain received signals; performing polyphase decomposition on the frequency domain received signals which are corrected using phase correction and acquiring polyphase signals; performing interpolation on the polyphase signals and acquiring the estimation values of the multi-antenna channel parameters with various linear combinations on each frequency; acquiring decorrelation array based on the pilot structure of the transmission antenna and decorrelating the estimation values of the multi-antenna channel parameters with various linear combination on each frequency using the decorrelation array and acquiring channel parameters of the pilot symbols on each frequency; acquiring channel parameters of data symbols based on the channel parameters of the pilot symbols. With the present invention, the inversion problem in multi-antenna channel estimation is avoided with lower complexity, and results of the multi-antenna channel estimation method become more accurate since the DFT and filtering are performed in the interpolation after polyphase decomposition.
摘要:
Disclosed is a transformer control device and method based on a three-dimensional zone diagram policy. The method includes: setting transformers, including a transformer A and a transformer B; collecting three-phase voltage data and three-phase current data in a power system; rectifying the collected three-phase voltage data and the three-phase current data; transferring the data to the latches in a time-transfer method; transferring the data to an A/D converter of a processor to convert analog signals to digital signals; constructing a three-dimensional zone diagram in the processor; determining transformer operating conditions according to positions of points formed by voltage, reactive power factor and substation load; and adjusting the transformers. This invention adopts a simple, easy and clear three-parameter control policy including voltage, power factors and substation loads, so as to simplify analysis of transformer operating conditions, realize optimal substation operation, reduce transformer loss, and increase economic benefits.
摘要:
A loudspeaker module includes a hollow main body, two rotatable connecting portions, and two loudspeakers. The hollow main body includes two opposite sidewalls. Each of the opposite sidewall defines a first opening, an inner sidewall of the first opening defines an annular rotating slot. One end of the connecting portion extends an annular flange shaped corresponding to the rotating slot. The two rotatable connecting portions are respectively rotatably connected to the main body via the flange rotating about the rotating slot. Two loudspeakers are disposed in an end of the corresponding rotatable connecting portion away from the main body.
摘要:
A pilot and channel estimation method for SDMA MIMO transmission downlink is provided in the present invention, and the method provides possibility for saving the orthogonal pilot resources; the pilot signals of different users in the transmitting antenna domain can occupy the same time-frequency resources, and thereby the pilot overhead of system resources can be reduced greatly; the method includes: for the MIMO transmission downlink that employs pre-coding for SDMA, taking the quantity of orthogonal pilot resources occupied by the users in the pre-coding domain as the number of data streams that can be transmitted or the number of spatial dimensions occupied first, at the transmitting end of the base station; then, performing SDMA transmission pre-coding for the orthogonal pilots in the pre-coding domain in the same way as the data signals, to obtain the pilot signals of the users in the transmitting antenna domain; wherein, the pilots of the users in the pre-coding domain can be orthogonal in the frequency domain or code domain, and the pilots of different users in the pre-coding domain can be identical or not identical to each other; the pilot signals of different users in the transmitting antenna domain can occupy the same time-frequency resources.
摘要:
The present invention provides a semiconductor laser package including a heat sink, a laser bar with a plurality of lasers on the heat sink, an insulated layer arranged between said heat sink and said laser bar, a solder layer combining said insulated layer with said laser bar, and a clearance crossing said solder layer defined between adjacent lasers.
摘要:
Disclosed is a transformer control device and method based on a three-dimensional zone diagram policy. The method includes: setting transformers, including a transformer A and a transformer B; collecting three-phase voltage data and three-phase current data in a power system; rectifying the collected three-phase voltage data and the three-phase current data; transferring the data to the latches in a time-transfer method; transferring the data to an A/D converter of a processor to convert analog signals to digital signals; constructing a three-dimensional zone diagram in the processor; determining transformer operating conditions according to positions of points formed by voltage, reactive power factor and substation load; and adjusting the transformers. This invention adopts a simple, easy and clear three-parameter control policy including voltage, power factors and substation loads, so as to simplify analysis of transformer operating conditions, realize optimal substation operation, reduce transformer loss, and increase economic benefits.
摘要:
Based on information associated with users, a social networking system recommends one or more groups for a target user to join or to create. Characteristics of the target user, characteristics of users connected to the target user, characteristics of candidate groups in the social networking system may be used to identify groups for recommendation. The social networking system may provide questions to the target user and recommend a group to the target user based on received answers to the questions. For example, the answers to the provided question identify one or more characteristics of the target user, which are used to select a group for recommendation. Additionally, the social networking system may recommend additional users for the target user to add or invite to a group based on characteristics of the target user, the additional users, and/or the group.
摘要:
Based on information associated with users, a social networking system recommends one or more groups for a target user to join or to create. Characteristics of the target user, characteristics of users connected to the target user, characteristics of candidate groups in the social networking system may be used to identify groups for recommendation. The social networking system may provide questions to the target user and recommend a group to the target user based on received answers to the questions. For example, the answers to the provided question identify one or more characteristics of the target user, which are used to select a group for recommendation. Additionally, the social networking system may recommend additional users for the target user to add or invite to a group based on characteristics of the target user, the additional users, and/or the group.